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LEGO Missing Piece Checker

Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece and leave with the element ID LEGO asks for, or a link to buy the part.

NASA Mars Science Laboratory Curiosity Rover

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21104 NASA Mars Science Laboratory Curiosity Rover

295 pieces in 94 part and color combinations.

Before you call it missing

Builders who report a missing piece often find it in one of these places. Tick each one off as you look.

Look-alike colors in this set

These parts appear in this set in two colors that are easy to confuse. If you are one short in one color, check whether it went in where the other color belongs. Each color has its own element ID in the parts list at the back of the instructions.

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Piece checklist

Technic Connectors 35 pieces

  • Technic Axle Connector with Axle Hole Black Part 32039 Element 4107081 or 3203926 ×18
  • Technic Axle and Pin Connector Angled #3 - 157.5° Black Part 32016 Element 6261386 or 4107082 ×5
  • Technic Pin Connector Round [Slotted] Black Part 62462 Element 6173119 or 4526982 ×4
  • Technic Axle and Pin Connector Angled #1 Dark Bluish Gray Part 32013 Element 32013199 or 6296856 ×4
  • Technic Axle and Pin Connector Perpendicular Dark Bluish Gray Part 6536 Element 6536199 or 6261374 ×2
  • Technic Pin Connector Plate 1 x 2 x 1 2/3 [Two Holes On Top] Dark Bluish Gray Part 32530 Element 4210763 ×2

Plates 34 pieces

  • Plate 1 x 1 Black Part 3024 Element 302426 1 spare in the box ×2
  • Plate 1 x 2 Dark Bluish Gray Part 3023 Element 4211063 ×2
  • Plate 1 x 3 Dark Bluish Gray Part 3623 Element 4211133 ×1
  • Plate 2 x 3 Dark Bluish Gray Part 3021 Element 4211043 ×4
  • Plate 8 x 16 Tan Part 92438 Element 4609726 ×2
  • Plate 1 x 1 White Part 3024 Element 6548262 or 302401 1 spare in the box ×4
  • Plate 1 x 2 White Part 3023 Element 6552100 or 6548261 ×5
  • Plate 1 x 4 White Part 3710 Element 6552108 or 6548266 ×3
  • Plate 1 x 6 White Part 3666 Element 6552107 or 6548265 ×3
  • Plate 2 x 2 White Part 3022 Element 6552099 or 6548260 ×4
  • Plate 2 x 6 White Part 3795 Element 6550146 or 379501 ×3
  • Plate 6 x 8 White Part 3036 Element 303651 or 303601 ×1

Bricks Sloped 29 pieces

  • Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Black Part 54200 Element 4504382 or 4287159 1 spare in the box Also in Dark Bluish Gray ×1
  • Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope) Dark Bluish Gray Part 54200 Element 4504378 or 4244373 1 spare in the box Also in Black ×2
  • Brick Sloped 33° 3 x 2 Dark Bluish Gray Part 3298 Element 4211106 ×20
  • Brick Sloped 30° 1 x 2 x 2/3 White Part 85984 Element 6550189 or 4547489 ×2
  • Brick Sloped 45° 2 x 1 with Bottom Pin White Part 3040b Element 6552115 or 4121932 ×2
  • Brick Sloped Inverted 34° 3 x 1 with Internal Stopper White Part 4287b ×2

Technic Axles 28 pieces

  • Technic Axle 2 Notched Black Part 32062 Element 4109810 or 3206226 ×10
  • Technic Axle 4 Black Part 3705 Element 370526 ×2
  • Technic Axle 4 with Stop Dark Bluish Gray Part 87083 Element 6083620 or 4560177 ×2
  • Technic Axle 3 with Stud Dark Tan Part 6587 Element 6031821 or 6013821 ×7
  • Technic Axle 3 Light Bluish Gray Part 4519 Element 4211815 ×4
  • Technic Axle 5 Light Bluish Gray Part 32073 Element 32073194 or 4211639 ×3

Tiles 25 pieces

  • Tile 1 x 1 with Groove White Part 3070b Element 6550138 or 307001 1 spare in the box ×12
  • Tile 1 x 2 with Groove White Part 3069b Element 6548264 or 306901 ×9
  • Tile 2 x 2 with Groove White Part 3068b Element 6548263 or 306801 ×4

Plates Special 22 pieces

  • Plate Special 1 x 2 with Long Towball Black Part 2508 Element 4274405 or 250826 ×2
  • Plate Special 2 x 2 x 2/3 with Two Studs On Side and Two Raised [Solid Anti-stud] Light Bluish Gray Part 99206 Element 4654577 ×2
  • Plate Special 1 x 1 with Clip Vertical [Thick U Clip] White Part 4085c Element 408501 ×2
  • Plate Special 1 x 2 with 1 Stud with Groove and Inside Stud Holder (Jumper) White Part 15573 Element 6550152 or 6051511 ×6
  • Plate Special 1 x 2 with Clip Horizontal on End White Part 63868 Element 6361170 or 4535737 ×6
  • Plate Special 1 x 2 with Door Rail White Part 32028 Element 6550168 or 4249563 ×1
  • Plate Special 2 x 2 with Bar Frame Octagonal, Reinforced, Completely Round Studs White Part 75937 Element 6009016 ×2
  • Plate Special 2 x 6 x 2/3 with 4 Studs on Side, 1 Support Wall on Bottom White Part 87609 Element 4560929 ×1

Plates Round Curved and Dishes 14 pieces

  • Plate Round 1 x 1 with Solid Stud Dark Bluish Gray Part 6141 Element 4210633 1 spare in the box ×5
  • Plate Round 1 x 1 with Solid Stud Trans-Red Part 6141 Element 6514051 or 6208450 1 spare in the box ×1
  • Dish 2 x 2 Inverted [Radar] White Part 4740 Element 6601845 or 474001 ×1
  • Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening) White Part 4032a Element 6601914 or 403201 ×3
  • Plate Round 2 x 2 with Rounded Bottom [Boat Stud] White Part 2654 Element 6601843 or 6552259 ×4

Wheels and Tyres 13 pieces

  • Tyre 30.4 x 14 Offset Tread [Centre Band] Black Part 92402 Element 4619323 ×6
  • Wheel 18 x 14 with Pin Hole, Fake Bolts and Shallow Spokes Light Bluish Gray Part 55981 Element 6109684 or 4299119 ×6
  • Wheel 18 x 14 with Pin Hole, Fake Bolts and Shallow Spokes White Part 55981 Element 6359828 or 6260609 ×1

Bricks 12 pieces

  • Brick 1 x 4 Dark Bluish Gray Part 3010 Element 4211103 ×2
  • Brick 2 x 4 Light Bluish Gray Part 3001 Element 4211385 ×2
  • Brick 1 x 2 White Part 3004 Element 6548257 or 4613964 ×2
  • Brick 1 x 3 White Part 3622 Element 6550143 or 362201 ×2
  • Brick 1 x 4 White Part 3010 Element 6550135 or 301001 ×2
  • Brick 2 x 6 White Part 2456 Element 6552122 or 4249698 ×2

Bricks Special 12 pieces

  • Brick Special 1 x 1 Studs on 4 Sides Dark Bluish Gray Part 4733 Element 4210700 ×1
  • Brick Special 1 x 1 with Headlight Dark Bluish Gray Part 4070 Element 4211044 ×1
  • Brick Special 1 x 2 with Grille Dark Bluish Gray Part 2877 Element 4210636 ×1
  • Brick Special 1 x 1 with Headlight White Part 4070 Element 6548267 or 407001 ×7
  • Brick Special 1 x 4 with 4 Studs on One Side White Part 30414 Element 6550167 or 4143254 ×2

Technic Pins 11 pieces

  • Technic Pin with Friction Ridges Lengthwise and Center Slots Black Part 2780 Element 4121715 or 278026 1 spare in the box ×1
  • Technic Axle Pin with Friction Ridges Lengthwise Blue Part 43093 Element 4309323 or 4206482 ×4
  • Technic Pin Long with Friction Ridges Lengthwise, 2 Center Slots Blue Part 6558 Element 4514553 ×1
  • Technic Axle Towball Light Bluish Gray Part 2736 Element 6443149 or 4211375 ×2
  • Technic Pin 1/2 without Friction Ridges Light Bluish Gray Part 4274 Element 4274194 or 4211483 1 spare in the box ×1
  • Technic Axle Pin without Friction Ridges Lengthwise Tan Part 3749 Element 4666579 or 4186017 ×2

Bricks Round and Cones 8 pieces

  • Cone 1 x 1 [Top Groove] Black Part 59900 Element 4529236 Also in Dark Bluish Gray ×3
  • Brick Round 1 x 1 Open Stud Dark Bluish Gray Part 3062b Element 4211090 ×1
  • Cone 1 x 1 [Top Groove] Dark Bluish Gray Part 59900 Element 4529240 Also in Black ×2
  • Brick Round 1 x 1 Open Stud White Part 3062b Element 6619283 or 306201 ×2

Tiles Special 8 pieces

  • Tile Special 1 x 2 Grille with Bottom Groove Pearl Gold Part 2412b Element 4490599 ×6
  • Tile Special 1 x 1 with Clip with Rounded Tips White Part 12825 Element 6030716 ×2

Minifig Accessories 7 pieces

  • Equipment Binoculars Dark Bluish Gray Part 30162 Element 4587887 or 4211051 ×5
  • Equipment Hose Nozzle / Gun with Side String Hole Simplified Light Bluish Gray Part 60849 Element 6641461 or 4515897 1 spare in the box ×2

Technic Bushes 6 pieces

  • Technic Bush Light Bluish Gray Part 3713 Element 6275844 or 6271817 1 spare in the box ×2
  • Technic Bush 1/2 Smooth with Axle Hole Semi-Reduced Light Bluish Gray Part 32123b Element 6271165 or 4211573 1 spare in the box ×4

Bars, Ladders and Fences 4 pieces

  • Bar 1L with Clip [Cut Edges and One Side Hole] [Gap in Clip] Dark Bluish Gray Part 48729b Element 6278155 or 4579234 1 spare in the box ×4

Plates Wedged 4 pieces

  • Wedge Plate 3 x 2 Left White Part 43723 Element 6552121 or 4179875 ×2
  • Wedge Plate 3 x 2 Right White Part 43722 Element 6552120 or 4179874 ×2

Technic Beams 4 pieces

  • Technic Beam 1 x 2 Thick with Pin Hole and Axle Hole Black Part 60483 Element 6265091 or 6006140 ×2
  • Technic Beam 1 x 3 Thin Dark Bluish Gray Part 6632 Element 6632199 or 6364452 ×2

Technic Bricks 4 pieces

  • Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening] Light Bluish Gray Part 32064b ×1
  • Technic Brick 1 x 2 [1 Pin Hole] White Part 3700 Element 6619284 or 370001 ×3

Tiles Round and Curved 4 pieces

  • Tile Round 2 x 2 with Bottom Cross Black Part 4150 Element 415076 or 415026 ×1
  • Tile Round 1 x 1 Light Bluish Gray Part 98138 Element 6284071 or 4650260 1 spare in the box ×2
  • Tile Round 2 x 2 with Bottom Stud Holder White Part 14769 Element 6601846 or 6044691 ×1

Hinges, Arms and Turntables 2 pieces

  • Turntable 2 x 2 Plate, Base Black Part 3680 Element 368076 or 368026 ×1
  • Turntable 2 x 2 Plate - Top Light Bluish Gray Part 3679 Element 4540203 or 4495467 ×1

Minifig Neckwear 2 pieces

  • Minifig Neckwear Bracket [One Stud] Light Bluish Gray Part 42446 Element 4211760 1 spare in the box ×2

Pneumatics 2 pieces

  • Pneumatic T-Piece (T Bar) [New Style] Light Bluish Gray Part 4697b Element 4211508 1 spare in the box ×2

Technic Steering, Suspension and Engine 2 pieces

  • Technic Steering Arm Small with Towball Black Part 6571 Element 4543367 or 4125370 ×2

Bricks Curved 1 piece

  • Brick Arch 1 x 4 White Part 3659 Element 6550145 or 365901 ×1

Flags, Banners and Signs 1 piece

  • Road Sign Clip-on 2 x 2 Round White Part 30261 Element 6317571 or 4116816 ×1

Minifig Shields, Weapons, & Tools 1 piece

  • Tool Hammer / Mallet Large Black Part 4522 Element 452226 ×1

Tick each piece as you find it, or mark it missing.

When a piece really is missing

Ask LEGO

LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for the set number and each piece's element ID, the number printed beside the piece in the parts list at the back of the instructions. This checker lists both.

Request a replacement from LEGO

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Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from older or second-hand sets.

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Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.

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